1/*-
2 * Copyright (c) 2004 Marcel Moolenaar
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/ctype.h>
33#include <sys/kdb.h>
34#include <sys/ttydefaults.h>
35
36#include <machine/gdb_machdep.h>
37#include <machine/kdb.h>
38
39#include <gdb/gdb.h>
40#include <gdb/gdb_int.h>
41
42static char gdb_rxbuf[GDB_BUFSZ];
43char *gdb_rxp = NULL;
44size_t gdb_rxsz = 0;
45static char gdb_txbuf[GDB_BUFSZ];
46char *gdb_txp = NULL;			/* Used in inline functions. */
47
48#define	C2N(c)	(((c) < 'A') ? (c) - '0' : \
49	    10 + (((c) < 'a') ? (c) - 'A' : (c) - 'a'))
50#define	N2C(n)	(((n) < 10) ? (n) + '0' : (n) + 'a' - 10)
51
52/*
53 * Get a single character
54 */
55
56static int
57gdb_getc(void)
58{
59	int c;
60
61	do
62		c = gdb_cur->gdb_getc();
63	while (c == -1);
64
65	if (c == CTRL('C')) {
66		printf("Received ^C; trying to switch back to ddb.\n");
67
68		if (kdb_dbbe_select("ddb") != 0)
69			printf("The ddb backend could not be selected.\n");
70		else {
71			printf("using longjmp, hope it works!\n");
72			kdb_reenter();
73		}
74	}
75	return (c);
76}
77
78/*
79 * Functions to receive and extract from a packet.
80 */
81
82int
83gdb_rx_begin(void)
84{
85	int c, cksum;
86
87	gdb_rxp = NULL;
88	do {
89		/*
90		 * Wait for the start character, ignore all others.
91		 * XXX needs a timeout.
92		 */
93		while ((c = gdb_getc()) != '$')
94			;
95
96		/* Read until a # or end of buffer is found. */
97		cksum = 0;
98		gdb_rxsz = 0;
99		while (gdb_rxsz < sizeof(gdb_rxbuf) - 1) {
100			c = gdb_getc();
101			if (c == '#')
102				break;
103			gdb_rxbuf[gdb_rxsz++] = c;
104			cksum += c;
105		}
106		gdb_rxbuf[gdb_rxsz] = 0;
107		cksum &= 0xff;
108
109		/* Bail out on a buffer overflow. */
110		if (c != '#') {
111			gdb_cur->gdb_putc('-');
112			return (ENOSPC);
113		}
114
115		c = gdb_getc();
116		cksum -= (C2N(c) << 4) & 0xf0;
117		c = gdb_getc();
118		cksum -= C2N(c) & 0x0f;
119		gdb_cur->gdb_putc((cksum == 0) ? '+' : '-');
120		if (cksum != 0)
121			printf("GDB: packet `%s' has invalid checksum\n",
122			    gdb_rxbuf);
123	} while (cksum != 0);
124
125	gdb_rxp = gdb_rxbuf;
126	return (0);
127}
128
129int
130gdb_rx_equal(const char *str)
131{
132	int len;
133
134	len = strlen(str);
135	if (len > gdb_rxsz || strncmp(str, gdb_rxp, len) != 0)
136		return (0);
137	gdb_rxp += len;
138	gdb_rxsz -= len;
139	return (1);
140}
141
142int
143gdb_rx_mem(unsigned char *addr, size_t size)
144{
145	unsigned char *p;
146	void *prev;
147	jmp_buf jb;
148	size_t cnt;
149	int ret;
150	unsigned char c;
151
152	if (size * 2 != gdb_rxsz)
153		return (-1);
154
155	prev = kdb_jmpbuf(jb);
156	ret = setjmp(jb);
157	if (ret == 0) {
158		p = addr;
159		cnt = size;
160		while (cnt-- > 0) {
161			c = (C2N(gdb_rxp[0]) << 4) & 0xf0;
162			c |= C2N(gdb_rxp[1]) & 0x0f;
163			*p++ = c;
164			gdb_rxsz -= 2;
165			gdb_rxp += 2;
166		}
167		kdb_cpu_sync_icache(addr, size);
168	}
169	(void)kdb_jmpbuf(prev);
170	return ((ret == 0) ? 1 : 0);
171}
172
173int
174gdb_rx_varhex(uintmax_t *vp)
175{
176	uintmax_t v;
177	int c, neg;
178
179	c = gdb_rx_char();
180	neg = (c == '-') ? 1 : 0;
181	if (neg == 1)
182		c = gdb_rx_char();
183	if (!isxdigit(c)) {
184		gdb_rxp -= ((c == -1) ? 0 : 1) + neg;
185		gdb_rxsz += ((c == -1) ? 0 : 1) + neg;
186		return (-1);
187	}
188	v = 0;
189	do {
190		v <<= 4;
191		v += C2N(c);
192		c = gdb_rx_char();
193	} while (isxdigit(c));
194	if (c != -1) {
195		gdb_rxp--;
196		gdb_rxsz++;
197	}
198	*vp = (neg) ? -v : v;
199	return (0);
200}
201
202/*
203 * Function to build and send a package.
204 */
205
206void
207gdb_tx_begin(char tp)
208{
209
210	gdb_txp = gdb_txbuf;
211	if (tp != '\0')
212		gdb_tx_char(tp);
213}
214
215int
216gdb_tx_end(void)
217{
218	const char *p;
219	int runlen;
220	unsigned char c, cksum;
221
222	do {
223		gdb_cur->gdb_putc('$');
224
225		cksum = 0;
226		p = gdb_txbuf;
227		while (p < gdb_txp) {
228			/* Send a character and start run-length encoding. */
229			c = *p++;
230			gdb_cur->gdb_putc(c);
231			cksum += c;
232			runlen = 0;
233			/* Determine run-length and update checksum. */
234			while (p < gdb_txp && *p == c) {
235				runlen++;
236				p++;
237			}
238			/* Emit the run-length encoded string. */
239			while (runlen >= 97) {
240				gdb_cur->gdb_putc('*');
241				cksum += '*';
242				gdb_cur->gdb_putc(97+29);
243				cksum += 97+29;
244				runlen -= 97;
245				if (runlen > 0) {
246					gdb_cur->gdb_putc(c);
247					cksum += c;
248					runlen--;
249				}
250			}
251			if (runlen == 1) {
252				gdb_cur->gdb_putc(c);
253				cksum += c;
254				runlen--;
255			}
256			if (runlen == 0)
257				continue;
258			/* Don't emit '$', '#', '+' or '-'. */
259			if (runlen == 7) {
260				gdb_cur->gdb_putc(c);
261				cksum += c;
262				runlen--;
263			}
264			if (runlen == 6 || runlen == 14 || runlen == 16) {
265				gdb_cur->gdb_putc(c);
266				cksum += c;
267				runlen--;
268			}
269			gdb_cur->gdb_putc('*');
270			cksum += '*';
271			gdb_cur->gdb_putc(runlen+29);
272			cksum += runlen+29;
273		}
274
275		gdb_cur->gdb_putc('#');
276		c = cksum >> 4;
277		gdb_cur->gdb_putc(N2C(c));
278		c = cksum & 0x0f;
279		gdb_cur->gdb_putc(N2C(c));
280
281		c = gdb_getc();
282	} while (c != '+');
283
284	return (0);
285}
286
287int
288gdb_tx_mem(const unsigned char *addr, size_t size)
289{
290	void *prev;
291	jmp_buf jb;
292	int ret;
293
294	prev = kdb_jmpbuf(jb);
295	ret = setjmp(jb);
296	if (ret == 0) {
297		while (size-- > 0) {
298			*gdb_txp++ = N2C(*addr >> 4);
299			*gdb_txp++ = N2C(*addr & 0x0f);
300			addr++;
301		}
302	}
303	(void)kdb_jmpbuf(prev);
304	return ((ret == 0) ? 1 : 0);
305}
306
307void
308gdb_tx_reg(int regnum)
309{
310	unsigned char *regp;
311	size_t regsz;
312
313	regp = gdb_cpu_getreg(regnum, &regsz);
314	if (regp == NULL) {
315		/* Register unavailable. */
316		while (regsz--) {
317			gdb_tx_char('x');
318			gdb_tx_char('x');
319		}
320	} else
321		gdb_tx_mem(regp, regsz);
322}
323